Mark Williams holds his nerve to beat world No2 Ali Carter

The 35-year-old two-time former world champion from Ebbw Vale clinched his 3-1 win with a break of 95, showing great composure after losing the previous frame on a re-spotted black.

Williams had set off by taking a low-scoring opening frame with four scoring visits, the highest of which was a run of 27, before a break of 43 saw him come from 48-12 behind to move 2-0 in front.

Englishman Carter, who won the Roewe Shanghai Masters earlier this month, looked like taking the next frame in one visit, but his break ended on 72.

Williams replied with a clearance to level the scores, meaning the black had to come back out again, and Carter potted it to halve his deficit.

It did not prove to be a turning point, though, with Williams falling just short of a century break in the next frame as he clinched his spot in the next round of the Glasgow tournament.

"Every time I was in the balls I felt as if I was going to make a decent break," Williams said on worldsnooker.com. "It's not easy to play well in these best-of-fives. The last time I played best-of-fives was in a pro-am in Ilford when the top prize was 500, and this week we're playing for 100,000."

Williams also had his say on Ronnie O'Sullivan's antics yesterday, when the former world number one had to be persuaded to pot the final black to complete a 147 break by referee Jan Verhaas.

Williams said: "I said when he was on 24 I thought he'd make a maximum. He should have potted the black without messing about, or played a double on it or played safe. But that's why people come to watch him, to see what he's going to do."

China's Ding Junhui followed Williams through to the next stage, beating England's Jimmy Michie 3-1. And Trowbridge cueman Stephen Lee joined the last-16 line-up by beating Chesterfield's Nigel Bond 3-2.